Locomotive valve-gear.



F. W. FRlTCHEY.

LOCOMOTIVE VALVE GEAR.

`wmlcmmm FILED 1AN.11,19|5.

1,138,207 Patented May 4, 1915 v g k l @MAMMA/bm C, M w

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FRANKLIN W. FRITCHEY, 0F COLUMBUS, OHIO, ASSIGNOR TO CONRAD FRI'I'CHEY, 0F

. SANDUSKY, OHIO.

LOCOIVIOTIVE VALVE-GEAR.

masser.

Specification of Letters Patent.

Patented May d, 1915.

Application iled January l1, 1915. Serial No. 1,672.

T0 all 'whom 'it may concern Be it known that I, FRANKLIN W. FRITCHEY, a citizen of the'UnitedStates, residing at Columbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Locomotive Valve-Gears, of whichthe following is a specification.

My invention relates to locomotive valve gears and has particular reference to what is today known among workers in the art as the Walschaert valve gear. It is equally well known that the chief characteristic of this machine is a constant lead for the valve for all positions of engine cut oli, the prime advantage of the lead being to cause pre admission of steam to the cylinder in order to cushion the heavy reciprocating parts forming the structure as a' whole. When the engine is running at high speed, this is very essential, but when starting from a stationary position, it is'foften very detrimental. Pre-admission of rsteam tok any cylinder, means that the piston must' operate against the pressure of steam in front of it before it reaches the end of its stroke, thereby materially reducing the eiectiveness of the opposing cylinder.

In view of the foregoing conditions, my invention has for its object the provision and arrangement of a structure particularly adapted to the Walschaert type `of motion, wherein means are provided for'locating the valve in a position of no lead when the engine control mechanism is in a full forward or fullreverse position and establishing a lead for an intermediate position. By the term intermediateposition I mean such positions as are commonly known as those accommodating high engine speed.

The preferred embodiment of my invention is shown in the accompanying sheet of drawings, in whichy similar characters of reference designate corresponding parts, and in which:

Figure 1 is a representation, somewhat diagrammatic, of a Walschaert valve gear embodying my invention shown applied to a locomotive engine cylinder and, Fig. 2 is an enlarged detail view of the link and block used on all engines equipped with the Walschaert gear, but modiiied in accordance with my invention.

In these drawings, the engine cylinder is shown at l, while its pistonis designated by thenumeral 2, this piston being located at the extreme end of its forward travel. The piston imparts motion to the cross head 3 through the medium of the piston rod 4; and to the main drive connection of the connecting rod 5 with the crank 6. This construction is all elementary and the style of gear referred to is also well known, comprising an eccentric rod 7 located approximately ninety degrees ahead of the drive crank 6, as is shown at 8. This particular location of the eccentric pin follows because an outside admissionfvalve or D-slide valve 9 has been shown, it being understood that where the piston type of valve is used, the eccentric pin is usually located approximately ninety degrees behind the drive crank. This eccentric rod connects at 10 to the foot support 11 of the link 12, this link being provided with the usual form of castings on each side to serve as trunnions to centrally pivot the link, as is shown at 13. Operating within the slot of the link 12 is the usual form of link block 14 connected with the radius rod 15, this latter being connected at 16 to the combination lever 17. This combination lever is pivotally attached to the valve cross head 18 at its upper end and to an arm 19 and connecting link 20 to the piston cross head 3, at its lower end. As shown, the gear is set for full position forward, but this position may be reversed by movement toward the rightof a member 21 attached to a bell crank 22 at one end and to the reverse lever (not shown) at its opposite end, this bell crank 22 being attached to the radius rod 15 through the medium of a link 23.

The foregoing is a comparatively simple illustration of thenow well known W'alschaert valve gear and in order to provide means whereby no lead is provided in full forward or full reverse position, I have enlarged the extreme lower and upper portions 24 of the slot 26 in the link, so that both side walls of the slot and the side walls of the block, when this block is centrall in their extreme position, are located apart distances equal to the full amount of lead calculated for the valve when it is in full high speed position. In other words, each side wall of the slot 26 is enlarged at each extremity a distance equal to the lead calculated for the valve when the engine is in high speed running position.

Therefore, yassuming the direction of rotionally cut out at this point an amount vra5 equal to the lead, there will be no lead of the valve when the link block is in the position shown, as is indicated by the drawings. Continuedl rotation of the driver causes a return of the cross head 3 and the instant the crank 6 leaves its dead center position, the forward port of the cylinder begins to open, permitting the admission of steam to the forward side of the piston 2. Further rotation of the driver to bring the crank to its opposite `'dead center position, will have moved the valve 9 to a position opposite from that shown in Fig. 1 and will have brought the link block wall 27 into engagement with the link wall28, thereby providing for no lead at this end Vof the cylinder. However, it will be noted that these enlarged slotted portions ofthe link gradually taper inwardly to normal size, a size accommodating a working it of the link block, all as is indicated at 29. Whenk the link block is moved to assume this position,

by` movement of the reverse lever, which means an earlier cut oif, lead will again be established to vcushion the reciprocating parts, since'to move the link block to this position means that the engine has gained some lspeed either forward or reverse.

It will thus beapparent that I have formed an improved structure closely following the Walschaert type of gear, wherein the desirable feature of no lead whenin full forward or full reverse position is had, but establishing this lead for all positions of the valve at ordinary or high enginev speed. Further, there does not exist a pound between the link block and the link as would appear at first glance, because of the fact that the crank pin and the eccentric pin are located apart by an angle approximating ninety degrees. It will be noted that, as the driver revolves for the next forty-five degrees or slightly more, the eccentric pin 8 traverses that portion of its circular movementl which imparts fastest linear movement to the link./ 'At the same time, thek crank pin rotates on that portion of its circle which gives a comparatively slow movement to the cross head 3. Consequently, the `link block wall 25 will remain in contact with the link wall 261 because of this greater horizontal movement of the lower end of the link and, therefore, the combination lever will fulcrum about its pivot 16 with the radius rod 15. As this driver rotates, however, the eccentric pin 8 will come to that lportion of its circular travel which gives the slowest horizontal vmovementv of the link and the crank 6 will come touthat portion of its circular travel which causes fastest horizontal movement and, therefore, the fulcrum point of lthe combination lever will be transferred `from Y its pivot connection 16 to its pivot connec-` tion with the valve cross head 18, and then, because ofthe increased speed of the cross head 3, the combination lever will force the radius rod 15 yrearwardly to bring the link block wall 27 into engagementwith the link wall 28. In view of the compound motiony set up between these lcrank Yand eccentric pins, it must beV apparent that the shiftingV ofthe link block. from lone position in the slot tofthe other, must'be gradual 'and unaccompanied by any violent shock, since the n Y transfer from one wall to the other occurs at thetime when the fulcrum point of the combination lever is changed from one pivot point to the other, thischange of fulcrum be clear that the shifting 'of the link block from engagement with the link wall 26 to position ofengagement with the link wall 28, is unaccompanied by a shock.

What I claim is: Y

1. In a locomotive valve gear, a valve, a centrally pivoted slotted link, means for aotuating said link by the means of the locomotive, connecting means between saidlink and said valve, a reverse lever, means for changing the cut off by movement of said lever, and supplemental means for locating said valvein a position` of no lead when said lever is in full forward or full reversepositiony and establishing a'lead for intermediate positions. L

2. In a locomotive valve gear, a valve', a centrally pivoted slotted arcuate link, means for actuating said link by movement of-the locomotive, connecting means between -said link and said valve, a block slidable in said link and forming a portion of said last named means, means for moving said block in said link to change the engine cut off, and supplemental means for locatingsaid valve in a position of no leady when said blockY is in full forward or full reverse position and establishing a Vlead when in intermediate positions.r f

3. In a locomotive valve gear, a valve, a centrally pivoted slotted arcuate link, means for actuating said link by movement of the locomotive, connecting means between said link and said valve, a block slidable in said slotted link and forming a portion of said last named means, both extremities of both side Walls of the slot in said link being additionally cut out so that When said block is centrally disposed in either extreme position of said link, the distance between its side Walls and their ooperating link Walls equals the full amount of lead calculated for said Valve when in full high speed running position, the intermediate portions of the y10 slot closely tting said block, and means for shifting said block in said slot.

In testimony whereof I affix my signature in presence of tWo Witnesses.

FRANKLIN W. FRITCHEY. Witnesses:

WALTER E. L. BooK, A. L. PHELPS.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, l

Washington, D. C." 

